s11q7Key - 1. Chem 171 Quiz 7 Version A To test for the...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 171 Quiz 7 Version A 1. To test for the presence of the copper (II) ion we add an aqueous solution of nitrite ion. Write the balanced chemical equation that shows the reaction between the complex ion of copper (II) ion formed in water (i.e., [Cu(H 2 O) 6 ] 2+ ) and nitrite ion resulting in a complex ion with a charge of 2 - . Show the states. What is the color of an aqueous solution of copper (II) ion. [Cu(H 2 O) 6 ] 2+ (aq) + 4 NO 2 - (aq) Æ [Cu(NO 2 ) 4 ] 2- (aq) + 6H 2 O(l) An aqueous solution of copper (II) ion is light blue. 2. The following questions refer to the experiment entitled ”Volumetric Analysis: An Acid- Base Titration”: The color change of an indicator takes place over a range of approximately how many pH units? Explain your answer to the above question. 2 pH units To see a distinct color in a mixture of two colors, you need one color to be about 10 times the intensity of the other. For this to take place, the concentration ratio [HIn] / [In ] needs to be greater than 10:1 or less than 1:10. This will occur when pH = pK a – 1 or pH = pK a + 1, respectively, giving a transition range of about two units. Chem 171 Quiz 7 Version B 1. How do you distinguish between sodium salts and potassium salts. Give details. Prepare a solution of each salt.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

s11q7Key - 1. Chem 171 Quiz 7 Version A To test for the...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online